1. Field Of The Invention:
The present invention relates to protective guards and covers for jet engines and more particularly relates to an improved guard for the intake of a jet engine wherein the guard includes specially shaped titanium rods that each extend forward of the jet engine and along an inclined path that forms a thirty degree (30.degree.) angle with the central longitudinal axis of the guard. The titanium rods are circumferentially spaced preferably less than ten degrees (10.degree.) apart, and converge at the forward end portion of the guard.
2. General Background:
Each year, numerous accidents occur when foreign objects enter the front intake of a jet engine. Several patents have issued for aircraft engine guards, each attempting to solve this problem.
As an example, U.S. Pat. No. 2,663,993 entitled "Deicing Apparatus" discloses a screen or mesh type cover that is flat and which surrounds the inlet of an aircraft power plant. The screen or grill is heated to remove ice therefrom during use.
A forwardly extending air duct screen is described in U.S. Pat. No. 2,969,941 entitled "Air Duct Screen With Locking Device". The screen includes structural members that are disposed in a spaced apart relation and concentrically about the longitudinal axis of the overall cage or framework.
A retractable guard for an air intake of an engine is described in U.S. Pat. No. 2,944,631 entitled "Retractable Guards For Air Intakes" issued to T. H. Kerry et al. The Kerry patent discloses a guard that includes two guard portions, each of which is mounted to pivot about an axis extending across the intake duct. The guard portions are disposed to pivot between an operative position in which the guard portions are together, and extend across the entire path of fluid flowing into the duct. One edge of the guard portion co-operates with a corresponding edge of the other guard portion and another edge of each guard portion co-operates with a wall of the duct, and an inoperative position, the guard portions are removed from the path of fluid flowing through the duct. The guard portions are so shaped as to conform with the wall of the duct against which they lie in the retracted position.
An example of a rotating deflector for aircraft engines having propellers is disclosed in U.S. Pat. No. 3,121,545 issued to N. S. Meletiou and entitled "Rotary Deflector For Aircraft Engine Intakes".
U.S. Pat. No. 3,196,598 entitled "Inlet Deflector For Jet Engines" issued to W. T. Olson describes an apparatus for obstructing the entry of birds and other foreign objects into aircraft jet engines during ground and flight operations.
An air intake guard for a gas turbine engine is the subject of U.S. Pat. No. 3,426,981. The intake guard has blades of streamline section arranged either radially or transversely. The main structure of each blade is rigidly connected from steel or titanium and the nose is made of a deformable materials so as to mushroom on being struck by a large foreign body such as a bird and thereby increase the shielding area.
A screen apparatus for an air inlet is the subject of U.S. Pat. No. 3,871,844 issued to Frank F. Calvin, Sr. The screen apparatus is particularly useful for preventing ingestion of birds into aircraft jet engines. A screen extends outwardly from the air inlet of the engine to define an exterior surface providing an oblique angle relative to the nominal path of the engine through the air. Birds or other foreign objects which strike the screen are deflected away from the screen and the air inlet by the contact with the oblique angle. A solid nose cone at the forward end of the screen provides an area of relatively high air pressure which tends to deflect objects away from the straight-on impact with the screen. The apertured exterior surface of the screen apparatus has an aggregate aperture area equal to or exceeding the air inlet area of the engine to permit unimpaired engine operation.
U.S. Pat. No. 4,149,689 entitled "Protective Screen For Jet-Engine Intake" issued Apr. 17, 1979 to John McDonald. In the McDonald device, the forwardly open intake end of a jet engine is screened against birds or other airborne objects using a conical cage formed of an array of metal rods converging on the engine axis, the rods being held together at the vertex of the cone by a solid tip and in am intermediate plane as well as by the cone base by a pair of metal rings. In flight, they are free to vibrate so as to shake off adhering ice particles. De-icing can be further promoted by feeding back exhaust gases from the rear of the engine to the interior of the cage through an external pipe.